Abstract: A photocurable hydrophilic polymer, coating composition and hydrophilic lubricating coating based on the same are provided. The photocurable polymer is formed by copolymerization of a polymerizable photosensitive monomer and a hydrophilic monomer. The photosensitive monomer comprises: 1) units containing a photosensitive structure; 2) units containing a tertiary amine co-initiator structure; and 3) units containing and unsaturated bond. The units containing the photosensitive structure are at least connected with the units containing the tertiary amine co-initiator structure through —OC(?O)—, and the units containing the unsaturated bond structure are connected with the units containing the photosensitive structure through the units containing the tertiary amine co-initiator structure. The photocurable hydrophilic polymer has a high photocurable efficiency, a simple preparation process, a high production efficiency, less environmental pollution, and hardly any cross-linking.